1. Field of the Invention
The present invention relates generally to roller chains, and specifically to devices for holding roller chain in position for repair.
2. Description of the Related Art
Roller drive chains for bicycles, motorcycles, and other machines are well known to be awkward to repair. Such chains occasionally must be shortened to maintain the proper operating tension. Links can also become damaged and must be replaced. Very heavy chains, such as those used with tractors and other heavy machinery, are particularly difficult to handle during repairs and maintenance.
When a damaged chain link must be replaced, it is desirable to repair the chain without removing it from its sprockets. This assures the correct length, alignment, and tension. The difficult and dirty job of removing and replacing the chain is also avoided by leaving the chain in place.
A number of devices are known for maintaining the links of a roller chain in alignment for repair. Known devices have a number of disadvantages. Some devices are held in the hand and use hand pressure to tighten the chain, leaving only one hand to work on the chain. Other devices are expensive, heavy, or awkward to work with. No device is known which is simple and inexpensive, adjusts easily, fits into tight spaces, and holds the chain firmly and taut in the right position. The following patents illustrate devices having these disadvantages.
U.S. Pat. No. 1,710,092 to Hitchcock discloses a chain repair tool for heavy chains which includes a primary finger, a secondary finger, a nut, a bevel gear, and a lever. A spring holds the teeth of the bevel gear in engagement with the nut. The chain is held by the fingers and a ratchet brings the end links together to place a coupling pin. The ratchet is then reset to the operate in the opposite direction and spread the fingers apart. The spring is not located between the fingers and does not act to bias the fingers apart.
U.S. Pat. No. 1,994,270 to Cetrano teaches a tool for use in repairing sprocket chains. The tool has a pair of chain couplers, of which one is slidable toward the other along a straight bar which penetrates the couplers. A pair of hand-levers moves the couplers toward each other.
U.S. Pat. No. 3,379,005 to Jones discloses a chain clamp having engaging jaws with hooks to engage the chain. The jaws move on a threaded bolt shank.
U.S. Pat. No. 4,394,810 to Womble teaches a chain link repair device for metal drive chains, combining a vise and a breaker pin. The two jaw-heads of the vise pull the links together with the correct tension. The two jaw-heads are connected by guide rods and an actuator bolt. The breaker pin facilitates removal of the center bearing pin in large chain drive links.
U.S. Pat. No 5,056,305 to Cole discloses a tool for separating chain links which has an elongated lead screw having a threaded shaft manually turned by finger lever or wrench nut. One jaw member is pivotally connected to a support member, while the other jaw member is pivotally connected to a travelling nut engaged with the lead screw. The jaws are coupled in scissors fashion.
U.S. Pat. No. 5,193,336 to King teaches a tool for removing a clip member from a master link an a chain member. The tool has a first plier jaw pivotally secured to a second plier jaw. Each plier jaw has a first and a second arcuate recess to hold the roller chain.
British Patent 171,020 discloses a chain rivet extractor in which the chain link is gripped between a pair of jaws. The jaws are attached to holders which project above and below the jaws. The jaws are connected by toggle links. A screwed stem moves the toggle links so that the jaws grip the chain link. A spring may be attached to the jaws in such a manner as to tend to close them. The springs are not located between the jaws and do not act to bias the jaws apart.
None of the above inventions and patents, taken either singularly or in combination, is seen to describe the instant invention as claimed. Thus a device to hold roller chain solving the aforementioned problems is desired.